I think Dylan is great for a girl. I love unisex names and I grow so very weary of everyone being SO dead set against them. People are going to use them, might as well get accustomed to it. I'd spell it Dylann.

I don't really have a problem with people using unisex names (I even named my daughter Kimberley, so I can't have a huge problem with it). It just drives me mad when people insist on changing the spelling to make it more girly. I'm sorry but adding extra letters does not change the name, and it's my opinion that if you don't like the original spelling then look again for a name with a spelling you do like.

I think if you need to spell a name differently in order to "feminize" it, there are a couple very horrible things going on here: 1) You're ashamed of your daughter's female-ness and wish to cover it up by giving her a male name, and 2) that you're only going to give her a long life of trouble with people mistaking her for a boy when they hear her name, and always spelling her name wrong.

Definitely just Dylan. Dillon makes it seem too masculine (even though it is technically a boys' name). Dylann and Dylanne make it look like Dil-Anne. The other suggestions such as Dylyn and Dylynne are just way too many Y's and don't look like names at all.